System for dynamically adjusting the working roll separation in rolling mills



1967 P .1. BARNIKEL ETAL 3, 5,

SYSTEM FOR DYNAMICALLY ADJUSTING THE WORKING ROLL SEPARATION IN ROLLINGMILLS Filed Oct. 22, 1964 4 Sheets-Sheet l INVENTORS.

PETER J. BARNIKEL a ROBERT F? FREEIDMAN @ME L, mam

their ATTORNEYS 5, 1967 P. J. BARNIKEL ETAL 3,355,925

SYSTEM FOR DYNAMICALLY ADJUSTING THE WORKING ROLL SEPARATION IN ROLLINGMILLS Filed Oct. 22, 1964 4 Sheets-Sheet 2 INVENTORS. PETER J. BARNIIKEL8 ROBERT F? FREEDMAN their ATTORNEYS 5, 1967 P. J. BARNiKEL ETAL3,355,925

SYSTEM FOR DYNAMICALLY ADJUSTING THE WORKING ROLL SEPARATION IN ROLLINGMILLS Filed Oct. 22, 1964 4 Sheets-Sheet 15 wk N R Q m wt mm wQm mNINVENTORS. PETER J. BARNIKEL 8 ROBERT P. FREEDMAN BY W 9m, wzw

their ATTORNEYS 1967 P. J. BARNIKEL ETAL 3,355,925

SYSTEM FOR DYNAMICALLY ADJUSTING THE WORKING ROLL SEPARATION IN ROLLINGMILLS Filed Oct. 22, 1964 4 Sheets-Sheet 4 INVENTORS. PETER J. BARNIKEL81 ROBERT P. FREEDMAN their ATTORNEYS United States Patent 3,355,925SYSTEM FOR DYNAMICALLY ADJUSTING THE ROLL SEPARATION IN ROLLING I PeterJ. Barnikel, New London, and Robert P. Freedman,

Waterford, C0nn., assignors to General Dynamics Corporation, New York,N.Y., a corporation of Delaware Filed Oct. 22, 1964, Ser. No. 405,749 9Claims. (Cl. 72-244) This application is a continuation-in-part of ourcopending application Serial No. 182,062, filed March 23, 1962, forActuating Device and now abandoned.

This invention relates to systems for controlling the separation of theworking rolls in rolling mills during mill operation and, moreparticularly, to a new and improved dynamic roll separation adjustingsystem capable of very accurate roll adjustment at extremely rapidrates.

Prior to the introduction of the modern tandem mill to the metalprocessing industry, it was not necessary to adjust the separation ofthe working rolls during operation of a rolling mill and the onlyadjustments which were made were of the preset type. Initially, suchpreset adjustments were accomplished by driving tapered steel wedgesbetween the roll bearing blocks and the mill frame with the aid of asledge hammer, the wedges being retained in place by friction when aload was applied to the rolls. Later, to provide a wider range ofadjustment of the preset roll separation, hand-operated screws weresubstituted for the wedges, thereby providing a bi-directional controlto improve the accuracy of setting the roll separation, and eventually,electrically-driven presetting screws were substituted for themanually-operated screws. As in the case of the wedge, the high frictionbetween the screw and its nut was effective to preserve the separationsetting when the rolling load was applied. At about the same time, itwas proposed to make the original steel wedge bidirectionally adjustableby replacing the sledge hammer with a lead screw; but this proposal wasnever put into practice.

With the advent of tandem rolling it became necessary to provideadjustment of the separation of the working rolls with metal in the millin order to maintain the constant mass flow which is required by thetandem proc: ess. To permit this adjustment, the electric adjustingscrew presetting motors were replaced with must larger electric motorswhich could be jogged to overcome the friction that had previouslyserved so well to hold the preset roll separation during operation. Morerecently, in response to an ever-increasing demand for higher qualityrolled strip material, attempts have been made to regulate the gauge ofthe finished strip with greater accuracy by adjusting the rollseparation in a controlled manner during rolling of the strip inresponse to measured gauge variations. Accordingly, the previously largeelectric screw motors, which were incapable of providing continuous rollseparation adjustment at rapid response rates, were replaced by evenlarger screw drive motors, supplemented by more sophisticated motorcontrols and antifriction bearings. Because of the very large massrequired in the rotor of the electric drive motor and the connectinggear train, the maximum response rate which it is possible to obtainwith such systems corresponds to a working roll acceleration in theorder of 0.1 inch per second per second, but the correctional demands ofhigh speed rolling mills can require accelerations up to five to tentimes that which is possible with the electrically driven screw.Consequently, when automatic gauge control is attempted withelectrically driven screws, a number of mill stands having dynamicseparation adjustment control must be used for correction, since only asmall fraction of the total correction is attainable in each stand.

One attempt to overcome these ditficulties is described in United Statespatent to Wheeler No. 2,961,901, where in the nuts for the two adjustingscrews of the rolling mill are provided with gear segments which aresimultaneously rotated by a hydraulically driven rack. Although thisarrangement provides some improvement in working roll adjustmentacceleration over the electric motor-driven screws, it still does notapproach the maximum control requirements of modern rolling mills forautomatic gauge control because of the high inertia of the nut systemand the very high flow rate required of the geared-down hydraulic drivesystem.

Accordingly, it is an object of the present invention to provide a newand improved system for adjusting the working roll separation duringoperation of a rolling mill which overcomes the above-mentioneddisadvantages of the prior art.

Another object of the invention is to provide a new and improved dynamicroll separation adjusting system which responds rapidly enough to permitcomplete automatic gauge regulation of the material being rolled in asingle mill stand.

A further object of the invention is to provide an adjusting system ofthe above character which is simple and efiicient in operation, may beinstalled easily in conventional rolling mill stands, and is capable ofproviding highly accurate roll separation settings.

These and other objects of the invention are attained by providing, in arolling mill stand having a fixed frame and a pair of working rolls, oneof which is adjustable relative to the other one in the plane of theworking roll axes soas to vary the roll separation, a wedge memberinterposed between the adjustable roll and the stand frame, hydraulicpiston means connected to the wedge member to impart motion theretoprependicularly to the direction of relative motion of the adjustableworking roll, and a layer of polytetrafluoroethylene interposed betweeneach of the wedge surfaces and the frame and the adjustable workingroll, respectively. Preferably, the layer of polytetrafluoroethylene isin the form of a fabric made of fibers of polytetrafluoroethylene so asto withstand the extreme pressures generated in a rolling mill whileproviding almost ideal anti-friction characteristics.

More particularly, the stand of the invention is preferably providedwith two separate adjusting systems interposed between the stand frameand a bearing chock at each end of that backup roll which appliespressure to the adjustable working roll. Within each adjusting systemare a backup wedge which is complementary to the movable wedge and abearing plate, both having surfaces which coact with the movable wedgesurfaces and both of which are provided with a removable insert plateupon which the layer of polytetrafluoroethylene is mounted. Moreover,inasmuch as the backup wedge must move perpendicularly to the directionof motion of the movable wedge and must have good lateral supportwithout permitting lateral motion, guide members coated with a poly:tetratluoroethylene surface are provided to guide the backup wedge inits motion. Furthermore, to assure proper alignment of the components ofthe adjusting device despite Wear of the polytetraflu-o-roethylene layerand manufacturing variations, the hydraulic piston is linked to thewedge member by a tie rod which extends through a central opening in thepiston and holds the piston against the adjacent end of the wedgemember. 1

Further objects and advantages of the invention will be apparent from areading of the following description in conjunction with theaccompanying drawings, in which:

FIG. 1 is a side view of a rolling mill stand provided with arepresentative roll separation adjusting system according to theinvention;

FIG. 2 is an end view of the mill stand shown in FIG. 1, looking fromthe right-hand side of FIG. 1 and partly broken away;

FIG. 3 is an enlarged fragmentary view in longitudinal section, takenalong the line 33 of FIG. 1 and looking in the direction of the arrows,illustrating the adjusting systern in greater detail; and

FIG. 4 is a plan view, partly in section, taken along the line 4--4 ofFIG. 3 and looking in the direction of the arrows.

In the typical embodiment of the invention illustrated in the drawings,a rolling mill stand includes a rigid frame 11 in which are mounted, asbest seen in FIG. 2, a lower backup roll 12, a lower working roll 13, anupper working roll 14, and an upper backup roll 15, all of the usualtype. Within each side of the frame 11 the lower backup roll issupported in a lower bearing chock 16 (only one being visible in FIG. 2)and each side of the lower working roll is supported and guided in asmaller bearing chock 17 which fits into a corresponding opening in thechock 16. Similarly, at each side of the frame the upper backup roll issupported in a bearing chock 18 and each side of the upper working roll14 is guided by a small bearing chock 19 which is received in acorresponding opening in the chock 18, each of these bearing chocksbeing mounted for vertical sliding motion in the usual manner so as topermit adjustment of the working r-oll separation.

As in convention-a1 mill stands, an electric screwdown system 20 ismounted at the top of the frame 11 in order to make any large scaleseparation adjustments which may be necessary before or between milloperations. This system includes the usual drive motor 21 along with areduction gear system 22, a worm gear 23, a splined screw 24 and alubricated nut 25 above the upper backup roll bearing chock 18 at eachside of the frame 11 and, in conventional apparatus, the screw 24 wouldhear through a breaker block directly upon the bearing chock 18.

In order to provide a highly accurate adjustment of the separation ofthe working rolls 13 and 14 during operation with a high accelerationrate in accordance with the present invention, however, a rapid responsehydraulically actuated adjusting mechanism 26 is inserted between thescrew 24 and the bearing chock 18 on one side of the frame 11 and anidentical adjusting mechanism 26' is inserted between the screw 24' andthe bearing chock 18' on the opposite side of the frame. Inasmuch as thetwo adjusting mechanisms and the associated apparatus are identical,only the left hand system 26 as viewed in FIG. 1 will be described indetail, corresponding parts of the other system being identified byprimed reference characters.

As shown in the enlarged views of FIGS. 3 and 4, the rapid responseadjusting mechanism 26 comprises a vertical support plate 27, on oneside of which a horizontal rectangular frame 28 and two verticalreinforcing plates 29 and 30 are attached by welding, for example, theplates 29 and 30 being connected to the frame 28 by two horizontalplates 31 and 32. On the other side of the vertical plate 27 a hydrauliccylinder 33 includes a piston 34 attached to a hollow central shaft 35which projects through both of the end Walls 36 and 37 of the cylinder.A tie rod 38, extending through the central opening of the hollow shaft35, has an enlarged head 39 hearing against one end of the shaft 35through a thrust washer 40 and, at the other end of the shaft, the tierod is threaded into a socket 41 connected by a neck portion to one endof a rectangular wedge member 42, the rim of the socket 41 engaging theshaft 35 through a spacer 43 and another thrust washer 44. With thismounting arrangement, slight variations in the position of the wedgemember 42 with respect to the piston 34, which may result frommanufacturing variations or from wear in the layers ofpolytetrafiuoroethylene which are described below, can be accommodatedto prevent the binding of the wedge 42 and piston 34 which would occurif they were constrained to exact alignment.

The cylinder 33 is arranged to receive hydraulic fluid on either side ofthe piston 34 through two conduits 45 and 46, as shown in FIG. 2, so asto be double acting with regard to the direction of control. Hydraulicfluid is supplied to the conduits 45 and 46 from a conventional controlunit 47 wherein fluid from a high pressure line 48 is supplied to one orthe other of the conduits 45 and 46 by a conventional control valve (notshown) within the unit 47 in accordance With a control signal applied bya cable 49, the fluid being returned from the control unit throughanother conduit 50. Preferably, the hydraulic system including theconduits 45 and 46, the internal control valve in the unit 47, and thecylinder 33 are capable of handling hydraulic fluid at pressures up toabout 4,000 psi. or higher.

In addition, to provide a control signal regulating the operation of thecontrol unit 47 a control system (not shown) which may be of the typedescribed in the copending application of Freedman, Barnikel andTorrance, Serial No. 150,738 filed Nov. 7, 1961 and now Patent No.3,197,986 entitled Control System for Rolling Mills is provided. Asdescribed in that application, the working roll force required to attaina desired reduction in the thickness of the material is determined inadvance of rolling from a variety of factors such as the thickness ofthe incoming material to be rolled, the temperature of the material, thetension of the strip of material entering and leaving the mill, thevelocity of the material passing through the mill, etc. and is comparedwith the actual force applied by the mill and a corresponding controlsignal is applied at the proper time to a Wedge control unit to producethe required force. Accordingly, a control signal, obtained in thatmanner or in any other appropriate manner and corresponding to thechange in force required to produce the desired thickness reduction isapplied to the control unit 47 through the cable 43 so as to control thedirection in which hydraulic fluid is applied to the cylinder 33.Inasmuch as there are two adjusting systems 26 and 26, one for each sideof the rolling mill, the necessary force to be applied to each side ofthe backup roll and working roll may be determined separately and thesystems '26 and 26' actuated separately, thereby enabling variations intemperature, incoming thickness, etc. which occur between one side ofthe mill and the other to be taken into account.

In order to provide a signal which represents the position of the wedgeat any instant, a linear potentiometer 52 is mounted at the side of thereinforcing plate 29, as shown in FIG. 4. A potentiometer control rod 53connected to the wedge 42 by an extension rod 54 moves with the wedge soas to cause the potentiometer 52 to produce in the cable 51 a controlsignal accurately representing the position of the wedge. In the methodof operation just described, wherein the necessary force is computed andcompared with the actual force and the wedge is moved so as to producethe desired force, the Wedge position signal is used only to control theinitial position of the wedge when the mill stand is being prepared foroperation. If desired, however, in other methods of oper-- ation, thesignal from the potentiometer 52 will be com-- pared with a desiredwedge position signal to control the position of the wedge.

In the typical embodiment illustrated in the drawings, the adjustingsystem 26 is releasably attached to the screw 24 while permittingrotation of that screw, by a horizontal bearing plate 55 which isaffixed to the top of the rectangular frame 28 and has a controlcircular recess 56 to receive a flange 57 at the lower end of the screw.The flange 57 is retained by an inwardly projecting lip 58 which extendsaround one half of the periphery of the recss 56 and a locking plate 59,slidably mounted in the top bearing plate 55, which is movable towardand away from the screw 24 so as to be extendable over the opposite edgeof the flange 57. To operate the locking plate 59, a lever 60, pivotallymounted on the top bearing plate 55 by a stud 61, is linked to the plateby a pin 62, and an actuating arm 63 slidable through an aperture in thesupport plate 27 is connected to the lever 60 at an elbow 64, as shownin FIG. 4. A releasable locking member 65 is provided in the plate 27 toretain the actuating arm and the lever in the position corresponding tothe closed position of the locking plate.

Below the laterally movable wedge 42, a backup wedge 66 is supportedbetween the members of the rectangular frame 28 and a crossbar 67,retaining plates 68 being mounted on the crossbar 67 and the frame 28 tolimit the downward travel of the backup wedge and retain it within theadjusting assembly. In the illustrated rolling mill stand a clearancehole 70 is provided in the backup wedge 66 to accommodate a pin 69 whichprojects from the top of the upper backup roll chock 18.

r In order to overcome the frictional resistance to motion, whichheretofore had defeated all previous attempts to use wedges for dynamicrolling mill adjustments no matter how well the wedges were lubricatedwith conventional lubricants, it is essential that an antifriction layerof a material having extremely low coefficients of static and slidingfriction be retained between the coacting surfaces of the movable wedge42, the bearing plate 55, and the backup wedge 66. Moreover, althoughthe polytetrafiuoroethylene material which is made by the E. I. du Pontde Nernours and Co. and is sold under the trademark Teflon has been usedin solid or sheet form to provide very low coeflicients of static andsliding friction, its tendency towards cold flow or plastic deformationmakes it undesirable as a bearing material for unit loads exceedingabout 3,000 p.s.i.

It has been discovered, however, that the tensile strength ofpolytetrafluoroethylene fibers is many times that of the solid or sheetform of the material. Conse quently, when polytetrafiuoroethylene fibersare woven into a fabric they form a surface having the lubricatingproperties of solid polytetrafluoroethylene but capable of withstandingloads of more than 20,000 p.s.i. without cold flow. One form of fabricwhich may be used for this purpose comprises a composite weave ofpolytetrafluoroethyh ene fibers with other fibers as described in theUnited States Patent to White No. 2,804,886. It has been found, however,as described in the copending application of Edward Hobaica, Serial No.395,468 filed Sept. 11, 1964, now Patent No. 3,283,718, and assigned tothe same assignee as the present application, that a fabric madeentirely of p-olytetrailuoroethylene fibers may be bonded to a cleanmetal surface by chemically etching one face of thepolytetrafiuoroethylene fabric, applying an adhesive material having anaffinity for metal to the metal surface, placing the etched fabricsurface on the adhesive covered metal surface, and applying heat andpressure to bond the fabric to the metal surface. For a more detaileddescription of the bonding method, reference may be had, if necessary,to the above-mentioned Hobaica application. In addition, it has beenfound that fabrics made entirely of polytetrafluoroethylene fibershaving a wearing quality superior to that of the composite fabric.Alternatively in certain cases, the polytetrafluoroethylene material maybe held in a metallic matrix of the type described, for example, inUnited States patent to Love No. 2,798,005 or may consist of a filledpolytetrafluoroethylene sheet of the type sold by the Dixon Corporationof Providence, Rhode Island under the trade name Rulon, in order to formthe antifriction layer.

In the illustrated embodiment of the invention both the bearing plate 55and the backup wedge 66 are provided with insert plates 71 and 72respectively at the surfaces facing the wedge 42 and each of theseplates has bonded to its outer surface a layer 73 and 74 respectively ofthe above-mentioned polyt-etrafluoroethylene fabric. These insert platesare retained in corresponding recesses in the bearing plate and thebackup wedge by a plurality of set screws 75. Also, to permit verticalmotion of the backup wedge 66 while resisting the laterally directedforce component the crossbar 67 has mounted on the side adjacent to thebackup wedge a guide shim 76 having a polytetrafiuoroethylene fabricbonded to its working surface in the manner previously described.Furthermore, to guide both the movable wedge 42 and the backup wedge 66along the sides adjacent to the rectangular frame 28, similar shims 77and 78 having polytetrafluoroethylene fabric surfaces are mounted on theframe members. Consequently, metal to metal contact of the movable wedgeand the backup wedge during operation is completely eliminated and thosewedges engage only surfaces which have extremely low coefficients ofstatic and sliding friction. In addition, flexible rubber seals 79mounted on the rectangular frame 28 and the crossbar 67 engage the sidesof the backup wedge 66 and sheet metal covers 80 and 81 are mountedabove and below the space between the vertical plates 29 and 30 to keepthe interior of the adjusting assembly 26 free of dirt.

In operation, with a layer of material to be rolled passing between theworking rolls 13 and 14 and with the screw 24 preset at a desiredsetting, a signal representing any change in the force which is requiredto produce a desired reduction in the thickness of the material isapplied through the cable 49 to the control unit 47. In response to thiscontrol signal, the internal valve (not shown) in the control unit movesto supply hydraulic fluid from the line 48 to one or the other of theconduits 45 and 46 to move the piston 34 in the proper direction toreduce the difference between the actual force applied and the requiredforce. As the wedge 42 moves to the left as viewed in FIG. 3, forexample, it drives the backup wedge 66 downwardly, thereby increasingthe pressure applied by the working rolls 13 and 14 so as to reduce thethickness of the material being rolled, and, as the wedge moves to theright the pressure is reduced so that the thickness of the material isnot decreased to as great an extent.

By virtue of the very small mass, in contrast to conventional apparatus,of the movable members of the adjusting system 26 including the piston34 and the wedge 42, the roll separation adjusting system of the presentinvention is enabled to make roll separation adjustments at very highacceleration up to, for example 0.8 inch per second per second whilecontrolling the separation very accurately, e.g., to less than threeten-thousandths of an inch. in fact, the accelerations attainable withthe piston and wedge arrangement of the present invention re not limitedby the inertia of the components being driven and any reasonableacceleration may be provided. In contrast, as pointed out above,conventional electrically driven screw controls are limited to about 0.1inch per second per second maximum acceleration and the hydraulicallyactuated screws described in Patent No. 2,961,- 901 are limited to about0.3 inch per second per second maximum acceleration by the systeminertias. Stated another way, the inertias of a comparable wedgeadjusting system of the present invention, a hydraulically driven screwsystem, and an electrically driven screw system are in the ratios of oneto one hundred to one hundred thousand. Also, in addition to having amass which is negligible compared to the driving force available and astatic friction which is about the same as its sliding friction, thecoefficient of friction of the polytetrafluoroethylene antifrictionlayer utilized in the present invention varies with the velocity of thewedge in such a way as to approach true viscous damping, which is highlydesirable in high speed servo mechanisms.

Exemplary of the high performance capabilities of the adjusting systemof the present invention is the fact that an adjusting system of thetype described herein, subjected to a total load of over two millionpounds and a pressure in the range of 5,000 to 10,000 p.s.i. on thepolytetrafiuoroethylene bearing surfaces was operated with continuousadjustment motion at varying rates for over 1400 hours without failure,consistently providing accurate adjustments at accelerations farexceeding those attainable with conventional apparatus.

Although the invention has been described herein with reference to aspecific embodiment, many modifications and variations therein willreadily occur to those skilled in the art. Accordingly all suchvariations and modifications are included within the intended scope ofthe invention as defined by the following claims.

We claim:

1. Apparatus for adjusting the working roll separation in a rolling millincluding a frame and first and second relatively movable working rollsdisposed within the frame comprising a wedge member having two surfacesdisposed at an angle interposed between the frame and the first workingroll and movable transversely therebetween so as to increase or decreasethe force urging the first working roll toward the second working roll,a first bearing member linked to the mill frame and having a bearingsurface coacting with one of the surfaces of the wedge member, a secondbearing member linked to the first working roll and having a bearingsurface coacting with the other surface of the wedge member, anantifriction layer including polytetrafiuoroethylene disposed betweeneach of the surfaces of the wedge member and the coacting surfaces ofthe first and second bearing members respectively, and hydraulic drivemeans including a piston connected directly to the wedge member toimpart said transverse motion thereto, including removable insert platesmounted in the first and second bearing members to provide the bearingsurfaces thereof, and means affixing the layer includingpolytetrafiuoroethylene to each of the insert plates so as to dispose itbetween the coacting surfaces of the wedge member, and the first andsecond bearing members.

2. Apparatus for adjusting the working roll separation in a rolling millincluding a frame and first and second relatively movable working rollsdisposed within the frame comprising a wedge member having two surfacesdisposed at an angle interposed between the frame and the first workingroll and movable transversely therebetween so as to increase or decreasethe force urging the first working roll toward the second working roll,a first bearing member linked to the mill frame and having a bearingsurface coacting with one of the surfaces of the wedge member, a secondbearing member linked to the first working roll and having a bearingsurface coacting with the other surface of the wedge member, anantifriction layer including polytetrafluoroethylen disposed betweeneach of the surfaces of the wedge member and the coacting surfaces ofthe first and second bearing members respectively, and hydraulic drivemeans including a piston connected directly to the wedge member toimpart said transverse motion thereto, including a hollow shaft on whichthe piston is mounted, and a tie rod extending through the hollow shaftand attached to the wedge member to hold one end of the shaft in rigidabutment with the wedge member but permit positional adjustments in theplane of abutment.

3. Apparatus for adjusting the working roll separation in a rolling millincluding a frame and first and second relatively movable working rollsdisposed within the frame comprising a wedge member having two surfacesdisposed at an angle interposed between the frame and the first workingroll and movable transversely therebetween so as to increase or decreasethe force urging the first working roll toward the second working roll,a first bearing member linked to the mill frame and having a bearingsurface coacting with one of the surfaces of the Wedge member, a secondbearing member linked to the first working roll and having a bearingsurface coacting with the other surface of the wedge member, anantifriction layer including polytetrafluoroethylene disposed betweeneach of the surfaces of the wedge member and the coacting surfaces ofthe first and second bearing members respectively, and hydraulic drivemeans including a piston connected directly to the wedge member toimpart said transverse motion thereto, wherein the second bearing memberis wedge-shaped to complement the shape of the wedge member, andincluding support means supporting the second bearing member for motionperpendicular to the transverse motion of the wedge member and guidemeans in the support means having a polytetrafluoroethylene surface toprovide lateral support for the second bearing member while permittingsaid perpendicular motion thereof.

4. Apparatus for adjusting the working roll separation in a rolling millincluding a frame and first and second relatively movable Working rollsdisposed within the frame comprising a wedge member having two surfacesdisposed at an angle interposed between the frame and the first workingroll and movable transversely therebetw-een so as to increase ordecrease the force urging the first working roll toward the secondWorking roll, a first bearing member linked to the mill frame and havinga bearing surface coacting with one of the surfaces of the wedge member,a second bearing member linked to the first working roll and having abearing surface coacting with the other surface of the wedge member, anantifriction layer including polytetrafluoroethylene disposed betweeneach of the surfaces of the wedge member and the coacting surfaces ofthe first and second bearing members respectively, and hydraulic drivemeans including a piston connected directly to the wedge member toimpart said transverse motion thereto, including screw leans mounted inthe mill frame and having a movable end to provide large scaleadjustments in the Working roll separation and locking plate meansreleasably locking the first bearing member to the movable end of thescrew means to provide said link to the mill frame.

5. A rolling mill comprising a mill frame, first and second relativelymovable working rolls disposed within the frame, and a pair of adjustingmeans interposed between the frame and each end of one of the workingrolls, respectively, each adjusting means comprising a Wedge memberhaving two surfaces disposed at an angle interposed bctween the frameand the first Working roll and movable transversely therebetween so asto increase or decrease the force urging the first working roll towardthe second working roll, a first bearing member linked to the mill frameand having a bearing surface coacting with one of the surfaces of thewedge member, a second bearing member linked to the first Working rolland having a bearing surface coacting with the other surface of thewedge member, an antifriction layer including polytetratluoroethylenedisposed between each of the surfaces of the wedge member and thecoacting surfaces of the first and second bearing members respectively,and hydraulic drive means including a piston connected directly andrigidly to the wedge member to impart said transverse motion thereto.

6. A rolling mill according to claim 5 wherein each of the first andsecond bearing members has a removable insert plate to provide thebearing surface thereof and wherein the layer includingpolytetrafinoroethylene comprises a fabric including fibers ofpolytetrafiuoroethylene bonded to each of the insert plates.

7. A rolling mill according to claim 6 wherein each of the adjustingmeans includes a hollow shaft on which the piston is mounted and a tierod extending through the hollow shaft and attached to the wedge memberto hold one end of the shaft in rigid abutment with the wedge member butpermit positional adjustments in the plane of abutment.

8. A rolling mill according to claim 7 wherein the second bearing memberof each adjusting means is wedgeshaped to complement the shape of thewedge member,

and each adjusting means includes support means supporting the secondbearing member for motion perpendicular to the transverse motion of theWedge member and guide means in the support means having apolytetrafiuoroethylene surface to provide lateral support for thesecond bearing member While permitting said perpendicular motionthereof.

9. A rolling mill according to claim 8 including a pair of screwsmounted in the mill frame each having a movable end directed toward acorresponding end of the first Working roll to provide large scaleadjustments in the Working roll separation, and locking plate means ineach adjusting means releasably locking the first bearing member of theadjusting means to the movable end of the corresponding screw to providesaid link to the mill frame.

References Cited UNITED STATES PATIENTS 1,821,483 9/1931 Shover et a1.72--244 2,798,005 7/1957 Love. 2,804,886 9/1957 \Vhite. 3,081,644-3/1963 Hud-gens et al 74-4243 3,197,086 8/1965 Freedman et a1 72244FRANCIS S. HUSAR, Primary Examiner.

1. APPARATUS FOR ADJUSTING THE WORKING ROLL SEPARATION IN A ROLLING MILLINCLUDING A FRAME AND FIRST AND SECOND RELATIVELY MOVABLE WORKING ROLLSDISPOSED WITHIN THE FRAME COMPRISING A WEDGE MEMBER HAVING TWO SURFACESDISPOSED AT AN ANGLE INTERPOSED BETWEEN THE FRAME AND THE FIRST WORKINGROLL AND MOVABLE TRANSVERSE THEREBETWEEN SO AS TO INCREASE OR DECREASETHE FORCE URGING THE FIRST WORKING ROLL TOWARD THE SECOND WORKING ROLL,A FIRST BERARING MEMBER LINKED TO THE MILL FRAME AND HAVING A BEARINGSURFACE COACTING WITH ONE OF THE SURFACES OF THE WEDGE MEMBER, A SECONDBEARING MEMBER LINKED TO THE FIRST WORKING ROLL AND HAVING A BEARINGSURFACE COACTING WITH THE OTHER SURFACE OF THE WEDGE MEMBER, ANANTIFRICTION LAYER INCLUDING POLYETRAFLUOROETHYLENE DISPOSED BETWEENEACH OF THE SURFACES OF THE WEDGE MEMBER AND THE COACTING SURFACES OFTHE FIRST AND SECOND BEARING MEMBERS RESPECTIVELY, AND HYDRAULIC DRIVEMEANS INCLUDING A POSTION CONNECTED DIRECTLY TO THE WEDGE MEMBER TOIMPART SAID TRANSVERSE MOTION THERETO, INCLUDING REMOVABLE INSERT PLATESMOUNTED IN THE FIRST AND SECOND REMOVING MEMBERS TO PROVIDE THE BEARINGSURFACES THEREOF, AND MEANS AFFIXING THE LAYER INCLUDINGPOLYTETRAFLUOROETHYLENE TO EACH OF THE INSERT PLATES SO AS TO DISPOSE ITBETWEEN THE COACTING SURFACES OF THE WEDGE MEMBER, AND THE FIRST ANDSECOND BEARING MEMBERS.